This invention relates to conductive windings.
Conductive windings are used, for example, in transformers and inductors. FIG. 1, for example, shows an inductor formed of wire 14 wound about a core 10. The core may be a permeable magnetic core (e.g., ferrite) or may be a simple permeable or non-permeable rod or air core. In general, a certain volume in the vicinity of the core of a magnetic component is available for a winding, or windings. In the inductor of FIG. 1, the length 16 of the winding (called the traverse) is fixed by the dimensions of the core, whereas the height 18 of the winding (called the build) might be limited by either the core dimensions or by other constraints imposed in the final application. Maximum efficiency of the inductor is achieved when the turns on the winding fill the entire volume defined by the allowable traverse and build. It can be shown that the highest possible proportion of the total allowable winding volume which can be occupied by conventional round wire (called the fill factor) is .pi./4 or about 75%. Additionally, for a given diameter of wire, even that fill factor can be achieved only for certain numbers of turns (e.g., when the build of the winding is an integer multiple of the diameter of the wire). By using rectangular cross-section wire, the unoccupied spaces between adjacent wires (which exist in the case of round wires) are largely eliminated and higher fill factors can be reached. However, for both round and rectangular cross-section wire, certain combinations of wire diameter and turns will require complicated arrangements of overlapping turns, or a multitude of parallel windings, to achieve high fill factors.